Improvement in boring and drilling tools



these settings iuto`seats` provided for their rel secured. i The blocks B B are made 'with dove- UNITED 'STATES' PATENTv OFFICE;

LORENZO DOW, OF FIERMONT, NEW YORK.

IMPROVEMENT IN BORING AND DRILLVING TOOLS.

Specification forming part of Letters Patent No. 5'), 14S, dated January 23, 11866;-antedated-January 10, 1866.

'To all whom it may concern: i

Be itknown that I, LORENZO DOW, ot'Piermont, in the county of Rockland and State of New York, have invented a new and useful Improvement in Tools for Boring or Drilling Stone and other Hard Substances; and I' do hereby declare that the following is a full, clear, and exact description of the same.

This invention relates more especially to the boring or drilling tool having its cutters composed of diamonds or other hard stones which is the subject-matter of Letters Patent of the United `States granted to Rodolphe Leschot, July 14;, 1863, but itis applicable to all boring and drilling tools in which diamonds or other hard stones are used for the cuttingfedges. A great ditiiculty which has had 1to be contended within the manufacture of this tool has been that of 'securing -the cutters inthe stock. The method heretofore adoptedl has been to fasten them into settings of copper or other ductile metal or alloy, and to solder or braze ception in the face of the annular steel stock; and it frequently occurs in the use of this method that the heat to which the stock is subjected in soldering in one cutter will loosen one which had previously-been soldered in."

With a view to obviate this difficulty and to secure the cutters iirmly in the stock, my ini veution consists in soldering or brazing the cutters into separate removable blocks ofsteel made with dovetail tongues and inserted into. dovetail grooves. in the stock, or otherwise attached to the stock in a suitable manneny To enable others to construct boring or drill ing tools according to my invention, I wil1, p'ro-,v ceed to describe it with vreference to the accom:V panying drawings, in which- I y Figure 1 is a side view of the cutter-stock and cutters, representing them in an inverted position. Fig. 2 is a face view of the same.

Similar letters of reference indicate corresponding parts i-n b oth iigures.

A A are the cutters, otdiamond orvother hard stone. B B are the'rem'ovable blocks', or steel or other hard metal, into which the said cutters are soldered or brazed, and C is the annular stock into which the said blocks are tail tongues a a, which are fitted to grooves b cut radially across the face of the stock O.

Vin a thin setting ot' copper or other ductile metal in the usual manner, are secured into the cavities or-seats drilled or otherwise pro-- vided 'in the faces of the blocks B B by inserting and soldering or glazing their aforesaid settings thereiuto while the said lblocks are detached frornth'e stock C, and whenthe said blocks have had the cutters thus secured in them their dovetail tongues u a, areinserted into their respective grooves b b in the face of the stock. e l

As it is diicult, if not impracticable, to obtain diamonds or other sufficiently-hard stones large enough to make cutters Wide enough to take singly the whole width of cut required, and perhaps ynot desirable to do so, the several cutters are set at different distances from the center ofthe stock, to cut in circles of greater o'r less radius. The cutters being so set, those which are nearer the inner circumference ofthe annular stock cut more at their outer sides or edges, and are subject in their `opera-tion to an outward pressure in a direction' from the axis of the stock', and those which are nearer the outer circumference of the' stock are subject to an inward pressure toward the axis thereof. This being the case, the dovetail tongues provided on the blocks of the last-mentioned cutters and Jthe grooves provided in the stock for their reception are tapered inward toward the axis of the stock, as shown at3 3 in Fig.

:2, andfzthe tongues provided on theblocks of the first-mentioned cutters and the grooves provided in the stock for their reception are tapered outward-from -the axis of the stock, as shown at 4 4: in the' same iignrc, and in this vway all ofthe said blocks and cutters are sustained against the pressure toward or from the axis; but those'cutters which 'are set in about the middle ofthe face ot' thestock, A like those at the top and bottorn'of Fig. 2,

being subject to no greater or less pressure toward than from the axis of the stock, have the tongues ot' their receiving-blocks and the grooves provided in the stock for' the reception of thel said tongues parallel ina direction toward and from the axis of the stock'.

. The removable blocks B B afford facility for the'repair or replacement of any one or more ofthe cutters without any danger of disturbing the others Instead of tlie bloeks B B being 4d ovettiled into removable blocks of steel or other'jhbrd into the stock, they might be screwed iu. metal, which 'are dovetailed o r otherwise se- What I claim as my in vention, and desire to cured in` the stock, substantially as herein-defsecure by Letters Patent, is"- scribed. Y

Attaching the diamonds or other Stones v LORENZO DOW. which constitute the cutters of thebovling-tool Witnesses: tothe stock by soldering, bmzing, or votherv l Ehalimv T. BROWN,' wise seeuringthe settings of the said stones J.-W. COOMBS'. 

